how do I make a GLOBAL (IN ALL SERVERS) VARIABLES
I what to create a clicker game when 1 person clicks it adds to the all time counter + if 1 person spends money it spends to everyone.
You can use MessagingService to communicate with all serves.
you can use data store service or memory store(never used memory service before so not sure if its a good option)
Memory Stores | Documentation - Roblox Creator Hub
Data Stores | Documentation - Roblox Creator Hub
I remember seeing a post just like this one that was solved but i can’t find it. Either what these two above me have answered your question adequately.
Like everyone else has said, datastores could work well. You could also try using webhooks/httpsservice
Can I ask what you are making that needs global variables?
Don’t use DataStores for this, use MemoryStores